WATERTOWN, Wis. — A Marine who volunteered for a second tour in Iraq because he felt his friends needed him has been killed, his father says.

Cpl. Matthew Zindars, 21, of the southern Wisconsin city of Watertown, died July 24 on patrol in Ramadi when a roadside bomb exploded, his father, Ken Zindars, told the Watertown Daily Times.

The Defense Department had not officially confirmed the death as of July 25. He is the 77th Wisconsinite killed in Iraq since the U.S. invaded in 2003.

Zindars graduated from Watertown High School in 2004. He joined the Marines at age 18, while he was still in school, his father told the newspaper.

He returned from his first tour in Iraq in October.

He volunteered to return because all his friends were going back and they needed help, Ken Zindars said. His unit’s duties included security and clearing roadways of explosives.

He was supposed to come home this October.

Ken Zindars said his son was “salt of the earth.”

“He was a great kid and never gave us any trouble,” Zindars told the Daily Times.

He said his son always wanted to be in the military and was “pretty proud to be a Marine.”

Jim Wendt, a Zindars family friend, answered the phone at Ken Zindars’ home. He said Ken Zindars was out. Of Matthew Zindars, he said, “He was a very good kid. Very dedicated to serving his country.”

Jim Moeller, the principal at Trinity-St. Luke’s Lutheran School at Watertown, told The Associated Press that Matthew Zindars attended the school from kindergarten until he graduated as an eighth-grader in 2000.

He described Zindars as a “good, solid, basic kid” with good grades.

He was well-behaved, but he always had a half-smile on his face whenever Moeller saw him, making the principal wonder if the boy was up to something.

Moeller said he’s not surprised Zindars chose to return to Iraq to help his comrades.

“That very much fits in with the kind of kid he was. He had his group of friends and he was always loyal. He was a friend to many people. Whatever way he could help, he was willing to do that,” Moeller said. “I can still see him in my mind’s eye right now. He will be missed. Very much so.”